Power-actuated shears



Jan. 21, 1930; c. DERFLER POWER ACTUATED SHEARS Fiied Aug. 22, 1928 INVENTOR CA'RL DERFLERI.

A TTORNE Y.

Patented Jan. 21, 1930 UNITED STATES PATENT OFFICE CARL DERFLER, OF PORTLAND, OREGON POWER-ACTUATED SHEABS Application filed August 22, 1928. Serial m5. ao1,195.

a fixed and a relatively movable blade of' v which the movable blade is pivoted to the I frame in a novel and advantageous manner affording freedom of vibratile action with full support to maintain its vertical alignment and operative contact with the fixed blade.

A further object of the invention is the provision of effective and relatively simple means to vary the length of stroke of the movable blade and depth of opening between the blades and to readily secure them in such adjusted positions.

A still further object of the invention is to provide guide devices of simple and practical construction whereby'the movable blade is maintained at all times in elficient cutting 5 engagement with the fixedjhlade.

Other objects and advantages of my invention, and objects relating to details of construction and arrangement of parts will be readily apparent in the course of the detailed description to follow. In the accompanying drawings wherein I have illustrated one form in which my invention may be embodiedq;

Figure 1 is a view in 'side elevation of appa- 5 ratus embodying my invention.

Fig. 2 is a fragmentary view in side elevation of the same on an enlarged scale, with portions thereof broken away.

Fig. 3 is a view in end elevation of Fig. 2.

Fig. iris a detached view in end elevation of the blade-holder element with blade at tached.

Fig. 5 is a view in cross section on line 5-5 of Fig. 2.

Referring to said views, the reference-numeral 1 indicates a steel shank having two parallel'plane sides 2 and 3 disposed in vertical directions and having ahandle 5 rigidly fixed at one end thereof. An electric motor 60 6' of the single phase type is rigidly mounted upon a bracket 7 which is in turn fixedly secured to the shank forward of the handle. Conducting wires 8 and 9 of an electric circuit including the motor respectively lead to a switch 10 of any suitable type and to said motor being carried through the handle in a single cord 11 which isdesirably fitted at its other-end with an attachment (not shown) for an electric light socket as a suitable source -of current. A trigger-device 12 is provided within reach of the fore-finger of the operator when grasping the handle by pressing which the switch 10 may be closed to energize the motor, said trigger being spring-pressed to open the switch when the operators finger 05 is withdrawn therefrom.

The forward portion of the shank 1 is curved downwardly in the same plane and at its lower extremi 13 a so-called lower knifeblade 14. is fixed y secured,as at 15. Said blade is secured upon the side 3 of the shank and has its shearing edge 16 substantially in line with said side of the shank. The blade 14 extends forwardly substantially in parallel lines with the handle and is tapered to a point to assist in penetration below or between thicknesses of the sheets to be cut and also extends at its rounded lower edge 17 below the extremity 13 of the shank.

Upon the forward edge of the downturned so portion 13 of the shank and spaced above said fixed blade is a' circular recess 18 open at its forward perimeter for approximately ninety degrees. A vibratory blade-holder 20 of sheet-steel of substantially the same thickness as the shank is formed with a rearwardly projecting arm 21 terminating in a head 22 of circular configuration adapted to be received in the recess 18'for oscillating movements. The thickness of said head is slightly reduced from the thickness of the shank.

H A stud 23 extends through a central aperture 25 in said head upon which the head is pivotably movable. Said stud projects upon each side thereof in screw-threaded pins 26 upon which circular plates 27 are threaded and which overlap the recess 18 to bear upon the shank at each side. Through such means the blade-holder is pivoted to oscillate in yertical directions upon the stud 23 atthe center of the head 22 and upon its periphery in the recess 18 while being guided against twisting by the plates 27, except to the relatively small extent to be explained later.

The lower edge of the blade-holder is offset, as at 28, where an upper blade 30 is fixedly secured having a shearing-edge 31 on its lower margin oppositely disposed to the edge 16 of the lower blade. An arm 32 ex- 'tends upwardly from said blade-holder and is operatively connected to a stud 33 whose enlarged, globular end 33' is received between blocks 3 1 and 35 of a pitman-head in a manner togive flexibilityto the connection.

The inner block 35 of said pitman-head is formed with a stem 36 bored and internally screw-threaded to receive a screw-threaded extensioirBT of a pitman-rod 38. A lock-nut 39 is provided on said extension engageable with the stem 36 to secure the pitman-head and rod in adjusted positions to vary its effective length and thus to govern the opening made between the two shear-blades.

The pitman-rod 38 is operatively connected at its rear end about an eccentrically rotatable crank-disk 40 rigidly connected to a wormwheel 11 and rotatively mounted upon a pin 42 extending laterally from the shank. A worm-pinion 43 keyed upon the forward extremity of the motor-shaft -15 is in mesh with said worm-wheel and provides the power for actuating the pitman-rod. An extensible coil-spring 46 is connected at one end to a forwardly projecting lug 47 of the pitmanrod and at its other end is secured to the shank, as at 48, and aids by its tension in the forward, working stroke of the pitman and in exercising at all times a salutory tension 'upon the actuating devices for the movable blade to take up any looseness therein.

A guide-arm 50 is rigidly connected to the depending extremity 13 of the shank and extends forwardly in substantial parallelism with the blade-holder 20 and has at its forward extremity a guide-screw 51 adjustably engaging the side of the holder between its connection with the pitman-head and the blade 30 and upon the forward edge of the holder whereby the holder with its blade 30 may be maintained in effective shearing engagement with the lower, fixed blade 14.

In view of the detailed description given, the operation of my novel power-shears may be briefly described as follows:

\Vhen the motor is energized by the operator pressing upwardly upon the trigger 12 the worm-wheel41 will be rotatably actuated to reciprocate the pitman-rod 38 and thereby oscillate thebladediolder 20 to cause the movable blade 30 to vibrate in the shearing engagement with the lower fixed blade 14. The extent of opening afforded between the blades and hence the eHectivelength ofthe stroke the screw-extension 37. The guide-devices 50-51 bearing upon the side of the blade holder serve to maintain at all times the blades in shearing contact. There being a slight amount of play in the upper end of the holder the sliding engagement of the guidescrew 51 upon the holder along its forward edge causes a very minute but effective disalignment of the upper blade across the lower blade to promote the shearing action.

The pivotal joint of the blade-holder 1n the shank is of very advantageous arrangement giving as it does a double bearing for the holder both internal and external of the head 22 and also provides side guides therefor in the circular plates 27.

My new shears are adaptable for the cutting of almost any variety of sheet material and in construction may be varied in details to accommodate the device to its desired purposes, which adaptations of structure as fall within the scope of the appended clalms are contemplated in the invention.

Having described my invention, what I claim as my invention, 1s:

1. Power actuated shears consisting in a supporting shank, a fixed blade secured at one end of said shank, a blade-holder provided with a blade and pivotally connected to said shank to oscillate in shearing relation to said fixed blade, said pivotal connections consisting in a circular opening recessed in one edge of said shank, a head-extension from said holder seated in and hearing at its periphery upon the walls of said recess, and side plates bearing upon each side of said shank to cover said recess and having a central stud afl'ording an internal bearing axially of said head-extension, and power-actuated means for oscillating said holder.

2. Power actuated shears consisting in a supporting shank, a fixed blade secured at one end of said shank, a blade-holder provided with a blade and pivotally connected to said shank to oscillate in shearing relation to said fixed blade, said pivotal connections consisting in a circular opening recessed 1n one edge of said shank, a head-extension from said holder seated in and bearing at its periphery upon the walls of said recess, said head extension being of less thickness than sald shank. and side plates bearing upon each s 1de of said shank to cover said recess and hav ng a central stud affording a central bearlng axially of said head-extension, means for exerting side pressure upon the blade-holder to maintain the blades in shearingcontact, and power-actuated means for oscillatlng said blade-holder.

CARL DERFLER.

of the blade-holder may be controlled by adj usting the length of the pitman-rod through .1 

